docs: def import_tree_corpus(path):
      """
      Import a text file of treebank trees.
  
      Arguments:
      ----------
          path : str, filename for tree corpus.
  
      Returns:
      --------
          list<LabeledTree> : loaded examples.
      """
      tree_list = LabeledTreeCorpus()
      with codecs.open(path, "r", "UTF-8") as f:
          for line in f:
              tree_list.append(create_tree_from_string(line))
      return tree_list